The Effect of Substrate Topography on Cathodic Delamination

The effect of substrate topography on cathodic delamination has been investigated using two different surface preparation methods: Abrasive blasting and mechanical grinding, respectively. Two types of iron-grit (fine and coarse) were used for the abrasive blasting and the grinded specimens were prepared by abrasive paper. The rate of delamination was found to depend on the interfacial transport from the artificial defect to the delamination front and the interfacial transport of cations was found to be reduced by a greater tortuosity of the coating-steel interface.

It was found that the tortuosity of the coating-steel interface can be controlled by e.g. the grain size of the blasting material and the speed of the applied abrasive. In other words the study showed that the surface preparation can be used to control and minimize the rate of cathodic delamination.